1. Field Of The Invention
The present invention relates to laser systems for medical, machining and military applications; and more particularly to solid state lasers which are compact, reliable for long term use and easily replaced in the field.
2. Description Of The Prior Art
Solid state lasers are those in which the gain medium is a solid material usually having the form of an elongated cylindrical rod. Typically, the rod is composed of crystalline material, a glass or a plastic doped with an active ion such as Nd.sup.3+ or Cr.sup.3+, which provides lasing action in a laser resonator defined by a pair of mirrors. In such lasers, the solid state laser rod reaches an active state ready to provide laser gain upon exposure to the light from a flashlamp.
Solid state lasers of the type described are subject to several problems. One of the problems is the difficulty of maintaining accurate alignment of the optics and components of the laser resonator. Oftentimes, lasers that have worked in a mechanically and thermally stable laboratory fail to operate properly when brought to a machine shop floor or a doctor's office, wherein physical jarring or even temperature changes cause the optics to go out of alignment. Another problem with solid state lasers is the relatively high cost thereof. Contributing to the high cost of solid state lasers are (1) the need for a heavy frame to keep the optics aligned, (2) a separate housing which protects against some dust, but is not usually air tight, and (3) an expensive heat exchanger/heat removal system. Heat is usually removed from the laser by water which circulates around the flashlamp and around the solid state laser rod. This water must be kept clean using filters which add to the expense of the system. A further problem presented by the use of water around the laser rod is the lengthy time required to heat the water to operating conditions. Alternative arrangements for removing heat from the laser rod operate by putting the rod in thermal contact with a solid material. These alternative arrangements also require a large mass to be heated to operating temperature and, consequently, cause the heat removal to be nonuniform, thereby creating optical distortions in the laser rod.